SEO is open for every one.You can optimize your pages for SERP but just curious about mysterious variable "authority".I think Google must have some authority variable or flag for particular website for particular keyword. I mean for example if there is organization "abcXYZ" and its well known to world so what you think about Google that it would set its authority variable for abcXYZ's website for abcXYZ keyword to true.Which means that no other website can outclass abcXYZ's website for abcXYZ keyword without taking into account how qualitative SEO has been done on it.
I think they use some kind of trust rank system, where each domain is given a score based on how much google trusts them. A good trustrank would increase the weight of any outbound links and may make the site rank above a similar site with lower trustrank.
But there are sites which are authority sites. They have many relevant links pointing to them. So getting a relevant link from a site with no relevant links pointing to it is different than a link from a site with 100 relevant links pointing to it. At least that is a theory.
We as internet users can look at a site and make a decision whether it is an authority site or not. The difficult question is to what extent google assigns and uses an authority or trustrank score for the site based on the factors we would consider important.